This is something I've kicked around for several years. Most of the bearing trees around here sadly have turned to compost. Locust, cottonwood, elm and hackberry just don't live that long. But here in Central Oklahoma, mostly to the east, the mighty pin oak (usually referred to as a burr oak in the notes) has a pretty good chance of still standing witness.
I don't know how many probable bearing trees I've ran into over the years that 100% identification just wasn't possible. This has been mostly due to not wishing to damage or destroy the tree. In 1875 there was a 10" burr oak..139 years later the tree is quite a bit larger. Oaks in this part of the country can heal themselves up pretty good in a hunnerd years. Lots of times there is no scar visible, possibly only a slight 'hump' in the bark.
So instead of tree being a definitive accessory, it winds up being only another scintilla of evidence added to a hunch derived by a grey-haired gent, addled by too much time in the sun. It would be soooo nice to run my hand over the I.D. scribed so many years ago.
I read about an old castle restoration in England where 600 year old timbers were x-rayed to determine their structural integrity. Now my oldest son is an industrial radiographer. He spends his days x-raying welds on ship hulls, jet turbines and petroleum pressure vessels. A lot of their equipment is mobile. I had to ask him about the possibility of shooting a tree to determine if there existed evidence buried within the tree. Sadly, most of the x-ray source material is just too powerful. He was of the opinion that something along the lines of dental quality equipment might be useful.
Recently I have spoken with him and technology has filled in the gaps. They now have some very portable equipment that utilized computer tomography (CT) for scanning. It can be a low strength source. So much that the veterinary field is using it for equine medicine.
Now I need a few 'patients' to test this out on. My window of opportunity to get a crew and the equipment might come with only a day or two notice...anywhere in a four or five state area around here. I'm wondering if any of you surveyors in Colorado, Kansas, Oklahoma, Texas or Arkansas have any good candidate trees?
I guess the only criteria would be to be pretty damn sure it's the real deal, and not too inaccessible (hopefully close enough to drive the equipment within the vicinity).
Anybody got any candidates?
WOW, I like the way you think!
I have long dreamed of GPR. Ground Penetrating Radar, to look for stones, in intersections.
Something along the lines of a TV screen, to see underground, from several angles, and make a 3d drawing of an object.
Mmmmm I have had candidates through the yrs. I take a boring tool to them.... and drill in, count rings, and look for a blaze, at the right approximate years. (Some trees get 2 growth rings in a year, if the weather is just right) and such as that.
Some of the originals here are hollow, with a hole pointing at the corner. Some are inaccessible, unless you can carry it a few miles. Some are just stump holes.
N
It would be great if it works, but I think you are looking for a VERY low contrast image.
Since the healed scribing is wood over wood, you are only looking for the differences in the re-grown wood versus original and that will be hard to see in a background of rough bark texture versus air.
If it works, it will probably be mostly due to differences in water content.
The procedure actually measures density. The resulting info can be processed with the software to measure, and contrast, the minute differences in density.
I'm pretty convinced that the slow growth "scar" and the original wood have a good difference in density. I have seen several "mirror images" of the actual scribe cuneiform that was created by the tree healing. These were cut off the tree and usually occupy a prominent spot near some old surveyor's desk..
The scar tissue is considerably less dense than the heartwood. I'm of the opinion that the proper angle and contrast could be easily achieved in the field to obtain a "pretty picture" of the scribed info.
Cost is a different story. The guys with the CT Scan equipment are expensive, and busy. Some of their work can run 8-10K a day. I'm just hoping that my oldest son can rise to his birthright of being one of the "Cash Boyz" and finagle a crew close-by that is thirsty with time on their hands...
>Sadly, most of the x-ray source material is just too powerful. He was of the opinion that something along the lines of dental quality equipment might be useful.
What about just strapping X-ray film to a tree, shielding it with an outer layer of lead, and using a weak source on the far side of the tree to make the exposure. You could leave the film in place for a day, for example.
Interesting idea, would be fun to be part of the R&D on a marketable package.
Don't know about potential sales volume though.
I use an increment borer to date the age of blazes. Its fairly non-destructive and works well for many species, especially conifers. Saves me from sawing a big hole in a tree when the increment borer has shown the blaze is definetly from a different era than the original survey.
Am often surprised by surveyors who've never used one. Its one of my most valued tools.
I'm not nearly as versed in these things as my son. I had similar thoughts as you. The way he explained it to me is all the distance, intensity and exposure time are calculated from a focal point. If a weak source, according to him, would not penetrate an object; continued exposure still won't penetrate the object. They are also restricted by the NRC on the amount of source exposure time. The regular x-ray equipment they have used in the past would just blast through the wood as if it weren't there.
That's why he was so excited about the mobile CT scan. A normal x-ray is focused on a specific point. Everything incidental to that plane would be either over exposed, under exposed, or blurry. The CT scan is a volume scan that can focus on every density difference in the subject and be processed into some striking imagery.
There are two aspects to the radiation. One is described by the energy or wavelength of the rays, which in an X-ray machine is usually set by the kilovolts of acceleration and perhaps the target material in its tube. The other aspect is the total exposure.
The wavelength may determine whether any, or what fraction, of the rays are absorbed or pass through the various densities of the object and the detector. If some small fraction passes through dependent on density, and will affect the film/detector, then increased exposure time and a weak source will build up an increased image, just like a longer exposure time in your film camera.
> The wavelength may determine whether any, or what fraction, of the rays are absorbed or pass through the various densities of the object and the detector. If some small fraction passes through dependent on density, and will affect the film/detector, then increased exposure time and a weak source will build up an increased image, just like a longer exposure time in your film camera.
What about background cosmic radiation, using some type of shielding to get it approximately collimated? An exposure time of a week hardly seems unworkable for many projects.
> I use an increment borer to date the age of blazes. Its fairly non-destructive and works well for many species, especially conifers. Saves me from sawing a big hole in a tree when the increment borer has shown the blaze is definetly from a different era than the original survey.
Does any see the irony here but me? 😀
I feller that goes by "clearcut" talking about using a borer instead a cutting a big hole. Perhaps it was my short time as a logger that made me notice. (We were very selective in our cuttings.)
I'm just funning Mr. Cut!!
I found these a few years back. I have no way of knowing how old the blaze marks are. Would your system answer that question?
I'm confident that a 3d image of what's inside the tree would be a good start.
The images I've seen of x-rayed timbers did show the annual rings. From that I believe one would be able to determine the approximate number of years that have elapsed since the blaze was made, if nothing else.
No irony at all Mr. E.
No sense putting a big hole in a tree wasting some of the clear wood and very possibly starting the center to start rotting. Not if you can disprove it being an original BT w/ an increment boring.
Should be noted though that if the increment borer indicates presence of a blaze at the approximate age of the original survey, I do recommend sawing a chunk out to verify there's scribing if there is no other supporting evidence. Not totally uncommon for a skin-up to occur 'round the time of the original survey which can only be disproved by visually verifying the scribing. Many areas here in N. Ca which had some logging going on around the time of the original surveys. Not uncommon for dragged logs to rub against standing timber, leaving a scar which looks quite similar to a surveyor's BT blaze.
For the purposing of testing the technology, I would first scan a known bearing tree before trying to find one so you'll know what you're looking for.
I have one that is still standing that I believe to be the patent tree from 1857. It is in Freestone County, Texas and has a "cat face" blaze on it. It's grown 12" since 1857. I estimated growth rate from similar species trees in the area that I could be sure I was on the right tree and worked a ratio out. It put the tree within a half of an inch and it's where the corner should have been.
You'll lose many an increment borer working on the oaks in Texas. 🙂 Soft woods like Pine are fine, and we have used them on it, but proving a 24" oak or hickory, we quit trying, even with "expert tutelage" and plenty of friction reducers.
Never had much trouble on the various species of oaks and assorted native hardwoods around here as far as boring. Much more problematic trying to count rings as the hardwoods aren't always very easy to discern.
Maybe things are just built tougher in Texas? I can't tell from here, but all I know is a few of the feller's from your parts that have passed through here have suffered from bull in the china shop syndrome. Not saying that's the general case, but if ever a strong northwestern wind blows me that ways, I'll have to try boring a tree or 2 just for curiousity sake.
There might be existing technology to help you test your theory.
http://www.treeradar.com/gazette_tree_checkup.pdf
http://www.treeringsociety.org/TRBTRR/TRBvol30_11-22.pdf
Sounds like it could be fun making the scans!
🙂 Good luck. 🙂
Just wondering how to attack the tree
Face on to the blaze? Or from the side first to see how deep it is? Then maybe you could develop some settings to get the image you are looking for. What about MRI equipment? would that work better than xrays?